The COD level in the circulating water is high
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The COD level in the circulating water of our company has been high recently. Maintain it at around 40 mg/L. The COD that can be replenished is very low, often at a level that cannot be detected. No leaks were found in the device either
There may be 3 reasons: first, the COD level in the added water exceeds the standard； Second, the fungi were not properly controlled ； Third is leakage. The solution is that, in such cases, the makeup water needs to be treated before it is used for replenishment ； Even if the COD of the makeup water just meets the standards, after being concentrated upon entering the circulating water system, its COD level will exceed the limits ； If it is the second type, it is necessary to increase the use of oxidizing or non-oxidizing algaecides in order to control algae in the circulating water system. Third, is your pump cooled by circulating water? Is there a possibility of leakage, and has it been checked? Have all heat exchangers, oil-cooling units, and other equipment that use circulating water been thoroughly checked!
There is likely a leak; it is necessary to test the return water lines of each unit for COD levels. In addition, each unit should be inspected – often the cause cannot be identified in just one attempt
What is your concentration multiplier set at?
COD stands for organic matter content, and organic substances such as oil residues, methanol, and alkanes can all cause extremely high values
I haven’t noticed that yet; next week I’ll check all the oil coolers.
The analysis is quite thorough; what’s left to do is to check and verify all areas related to oil. The methanol has already been checked and no leaks were found. But in the case of a leak in an oil cooler, the liquid level should change first. I’ll take samples from all those areas next week for further analysis and verification.
Take a look at the oil pressure and the circulating water pressure to see how they are connected
If I keep it at 7-8 here, the COD will already be around 40